Muscle contraction and polymer-gel phase transitions

2000 ◽  
Author(s):  
Gerald H. Pollack
Keyword(s):  
Phase Transitions ◽  
Muscle Contraction ◽  
Polymer Gel ◽  
Gel Phase

Polymer-Gel Phase-Transition as the Mechanism of Muscle Contraction

1999 ◽  
Vol 600 ◽  
Author(s):  
Gerald H. Pollack
Keyword(s):  
Phase Transition ◽  
Optimal Design ◽  
Muscle Contraction ◽  
Design Principles ◽  
Maximum Strength ◽  
Artificial Muscles ◽  
Polymer Gel ◽  
Contraction Mechanism ◽  
Gel Phase ◽  
Cross Bridges

AbstractThe thesis offered here is that the muscle-contraction mechanism is similar to the mechanism of contraction in many artificial muscles. Artificial muscles typically contract by a phasetransition. Muscle is thought to contract by a sliding-filament mechanism in which one set of filaments is driven past another by the action of cyclically rotating cross-bridges—much like the mechanism of rowing. However, the evidence is equally consistent with a mechanism in which the filaments themselves contract, much like the condensation of polymers during a phasetransition. Muscle contains three principal polymer types organized neatly within a framework. All three can shorten. The contributions of each filament may be designed to confer maximum strength, speed and versatility on this biological machine. The principles of natural contraction may be useful in establishing optimal design principles for artificial muscles.

Engineering highly swellable dual-responsive protein-based injectable hydrogels: the effects of molecular structure and composition in vivo

2017 ◽  
Vol 5 (11) ◽  
pp. 2285-2294 ◽  
Author(s):  
V. H. Giang Phan ◽  
Thavasyappan Thambi ◽  
Bong Sup Kim ◽  
Dai Phu Huynh ◽  
Doo Sung Lee
Keyword(s):  
Molecular Structure ◽  
Phase Transitions ◽  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Bovine Serum ◽  
Injectable Hydrogels ◽  
Dual Responsive ◽  
Gel Phase

Highly swellable, dual-responsive bovine serum albumin (BSA)-based injectable hydrogels that exhibit sol-to-gel phase transitions in response to the physiological pH and temperature have been developed.

scholarly journals Swelling of polyacrylamide-based hydrogel in aqueous solutions of low-molecular salts

2020 ◽  
Vol 64 (3) ◽  
pp. 293-299
Author(s):  
E. V. Vorobieva
Keyword(s):  
Sodium Chloride ◽  
Potassium Chloride ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
External Solution ◽  
Swelling Kinetics ◽  
Polymer Gel ◽  
Molecular Salts ◽  
Gel Phase ◽  
Kinetics Of

The swelling kinetics of cross-linked polyacrylamide was studied depending on the composition of the external solution. It was shown that the polymer gel swelling during the transition from water to a potassium or sodium chloride solution and vice versa sharply decreases, then gradually increases. The swelling of gel in a solution of sodium chloride is higher than that of potassium chloride. In the equilibrium swollen gel, the concentration of salts in the gel phase is higher than in the external solution and increases with the transition from potassium chloride to sodium chloride.

Polymer Gel Phase Transition: The Molecular Mechanism of Product Release in Mucin Secretion?

1992 ◽  
pp. 671-681 ◽  
Author(s):  
Pedro Verdugo ◽  
Ingrith Deyrup-Olsen ◽  
Arthur W. Martin ◽  
Daniel L. Luchtel
Keyword(s):  
Phase Transition ◽  
Molecular Mechanism ◽  
Polymer Gel ◽  
Mucin Secretion ◽  
Product Release ◽  
Gel Phase

Phase transitions of liposomes: When light meets heat

2021 ◽  
Author(s):  
C S Velez-Saboyá ◽  
J R Guzmán-Sepúlveda ◽  
Jesus Carlos Ruiz-Suárez
Keyword(s):  
Differential Scanning Calorimetry ◽  
Phase Transitions ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Membrane Thickness ◽  
Scanning Calorimetry ◽  
Contraction Process ◽  
Exothermic Process ◽  
Gel Phase ◽  
Derivatives Of

Abstract Phase transitions of liposomes are normally studied by differential scanning calorimetry (DSC). A suspension of liposomes is subjected to an increase (decrease) of temperature and when heat is absorbed (released), the liposomes transit from a gel (liquid) to a liquid (gel) phase. This endothermic (exothermic) process takes place at a temperature called the melting temperature Tm, which is distinctive of the type of lipids forming the vesicles. The vesicles, though, also modify their size in the transition. Indeed, the thickness of the membranes decreases (increases) because carbon tails misalign (align). Concomitant with the modifications in the membrane thickness, the diameter (D) of the liposomes changes too. Therefore, when they are inspected by light, the scattered signal carries information from such dilatation (contraction) process. We performed careful experiments using dynamic light scattering (DLS) as a function of temperature to detect the size changes of different liposomes. Gaussian fits of the derivatives of the D vs T curves coincide within 1% with thermograms, which hints to the possibility of performing thermodynamic studies of lipid systems employing light.

Bioresorbable polypeptide-based comb-polymers efficiently improves the stability and pharmacokinetics of proteins in vivo

2017 ◽  
Vol 5 (4) ◽  
pp. 837-848 ◽  
Author(s):  
Md. Hasan Turabee ◽  
Thavasyappan Thambi ◽  
Jae Seung Lym ◽  
Doo Sung Lee
Keyword(s):  
Growth Hormone ◽  
Phase Transitions ◽  
Human Growth Hormone ◽  
Human Growth ◽  
Sustained Delivery ◽  
Amphiphilic Copolymers ◽  
Comb Polymers ◽  
Gel Phase ◽  
The Stability

Polypeptide-based comb-like amphiphilic copolymers that exhibits sol-to-gel phase transitions in response to physiological pH and temperature have been developed for the sustained delivery of human growth hormone.

Prolonged Chaotic Oscillations During the Gel/Xerogel Transition in Silicon Tetramethoxide Polymerization as Detected by Pyrene Excimerization.

1986 ◽  
Vol 73 ◽  
Author(s):  
Vered R. Kaufman ◽  
David Avnir
Keyword(s):  
Phase Transitions ◽  
Excited State ◽  
Driving Forces ◽  
Sol Gel ◽  
Chaotic Oscillations ◽  
Gel Structure ◽  
Adsorption Sites ◽  
Surface Active Agents ◽  
Surface Active ◽  
Gel Phase

ABSTRACTWhen the polymerization of Si(OCH3)4 is carried out in the presence of surface active agents, prolonged oscillations (over 1000 hrs) at the gel/xerogel transition are observed. The oscillations are of large amplitude, they are slow (several hrs/period), and they exhibit a chaotic behaviour. The probe by which these oscillations are observed is emission from excited state monomeric and excimeric pyrene. It is suggested tentatively that the driving forces for this oscillation are the structural relaxation of the secondary polymeric gel structure and the dispersion of adsorbed pyrene to thermodynamically favored adsorption sites. Relevant models could be those of oscillatory sol/gel phase transitions and of oscillatory polymerization reactions. We are unaware of previous observations of oscillations in sol/gel systems.

Directed Motion and Cargo Transport Through Propagation of Polymer-Gel Volume Phase Transitions

2005 ◽  
Vol 17 (15) ◽  
pp. 1869-1873 ◽  
Author(s):  
L. Yeghiazarian ◽  
S. Mahajan ◽  
C. Montemagno ◽  
C. Cohen ◽  
U. Wiesner
Keyword(s):  
Phase Transitions ◽  
Polymer Gel ◽  
Directed Motion ◽  
Volume Phase ◽  
Cargo Transport
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